Microwave Field-Detecting Needle Assemblies, Methods of Manufacturing Same, Methods of Adjusting an Ablation Field Radiating into Tissue using Same, and Systems Including Same

ABSTRACT

A method of adjusting an ablation field radiating into tissue includes the initial steps of providing an energy applicator and providing one or more microwave field-detecting needle assemblies. Each microwave field-detecting needle assembly includes one or more rectifier elements capable of detecting microwave field intensity via rectification. The method includes the steps of positioning the energy applicator and the one or more microwave field-detecting needle assemblies in tissue, transmitting energy from an energy source through the energy applicator to generate an ablation field radiating about at least a portion of the energy applicator into tissue, and adjusting the ablation field radiating about at least the portion of the energy applicator into tissue based on at least one electrical signal transmitted by the one or more microwave field-detecting needle assemblies.

BACKGROUND

1. Technical Field

The present disclosure relates to electrosurgical devices suitable foruse in tissue ablation applications and, more particularly, to microwavefield-detecting needle assemblies, methods of manufacturing the same,methods of adjusting an ablation field radiating into tissue using thesame, and systems including the same.

2. Discussion of Related Art

Treatment of certain diseases requires the destruction of malignanttissue growths, e.g., tumors. Electromagnetic radiation can be used toheat and destroy tumor cells. Treatment may involve inserting ablationprobes into tissues where cancerous tumors have been identified. Oncethe probes are positioned, electromagnetic energy is passed through theprobes into surrounding tissue.

In the treatment of diseases such as cancer, certain types of tumorcells have been found to denature at elevated temperatures that areslightly lower than temperatures normally injurious to healthy cells.Known treatment methods, such as hyperthermia therapy, heat diseasedcells to temperatures above 41° C. while maintaining adjacent healthycells below the temperature at which irreversible cell destructionoccurs. These methods involve applying electromagnetic radiation toheat, ablate and/or coagulate tissue. Microwave energy is sometimesutilized to perform these methods. Other procedures utilizingelectromagnetic radiation to heat tissue also include coagulation,cutting and/or ablation of tissue.

Electrosurgical devices utilizing electromagnetic radiation have beendeveloped for a variety of uses and applications. A number of devicesare available that can be used to provide high bursts of energy forshort periods of time to achieve cutting and coagulative effects onvarious tissues. There are a number of different types of apparatus thatcan be used to perform ablation procedures. Typically, microwaveapparatus for use in ablation procedures include a microwave generatorthat functions as an energy source and a microwave surgical instrument(e.g., microwave ablation probe) having an antenna assembly fordirecting energy to the target tissue. The microwave generator andsurgical instrument are typically operatively coupled by a cableassembly having a plurality of conductors for transmitting microwaveenergy from the generator to the instrument, and for communicatingcontrol, feedback and identification signals between the instrument andthe generator.

The particular type of tissue ablation procedure may dictate aparticular ablation volume in order to achieve a desired surgicaloutcome. Ablation volume is correlated with antenna design, antennaperformance, antenna impedance, ablation time and wattage, and tissuecharacteristics, e.g., tissue impedance.

Because of the small temperature difference between the temperaturerequired for denaturing malignant cells and the temperature normallyinjurious to healthy cells, a known heating pattern and precisetemperature control is needed to lead to more predictable temperaturedistribution to eradicate the tumor cells while minimizing the damage tosurrounding normal tissue. In some cases, it may be difficult for thephysician to determine when a microwave ablation probe is inserted to aproper depth within tissue, e.g., to reach the location of the ablationsite and/or to avoid unintended radiation exposure.

SUMMARY

The present disclosure relates to method of adjusting an ablation fieldradiating into tissue including the initial steps of providing an energyapplicator and providing one or more microwave field-detecting needleassemblies. Each microwave field-detecting needle assembly includes oneor more rectifier elements capable of detecting microwave fieldintensity via rectification. The method includes the steps ofpositioning the energy applicator and the one or more microwavefield-detecting needle assemblies in tissue, transmitting energy from anenergy source through the energy applicator to generate an ablationfield radiating about at least a portion of the energy applicator intotissue, and adjusting the ablation field radiating about at least theportion of the energy applicator into tissue based on at least oneelectrical signal transmitted by the one or more microwavefield-detecting needle assemblies.

The present disclosure also relates to method of adjusting an ablationfield radiating into tissue including the initial steps of providing anenergy applicator operably coupled to an energy source and providing oneor more microwave field-detecting needle assemblies. Each microwavefield-detecting needle assembly includes one or more rectifier elementscapable of detecting microwave field intensity via rectification. Themethod includes the steps of positioning the energy applicator and theone or more microwave field-detecting needle assemblies in tissue,transmitting energy from the energy source through the energy applicatorto generate an ablation field radiating about at least a portion of theenergy applicator into tissue, and adjusting the ablation fieldradiating about at least the portion of the energy applicator intotissue by adjusting at least one operating parameter associated with theenergy source based on at least one electrical signal transmitted by theone or more microwave field-detecting needle assemblies.

The present disclosure also relates to a microwave ablation controlsystem including a microwave field-detecting needle assembly and acontrol unit in operable communication with the microwavefield-detecting needle assembly. The microwave field-detecting needleassembly includes at least one rectifier element capable of detectingmicrowave field intensity via rectification. The microwave ablationcontrol system also includes an electrosurgical power generating sourcein operable communication with the control unit and an energy-deliverydevice operably coupled to the electrosurgical power generating source.

BRIEF DESCRIPTION OF THE DRAWINGS

Objects and features of the presently-disclosed microwavefield-detecting needle assemblies, methods of manufacturing the same,methods of adjusting an ablation field radiating into tissue using thesame, and systems including the same will become apparent to those ofordinary skill in the art when descriptions of various embodimentsthereof are read with reference to the accompanying drawings, of which:

FIG. 1 is a perspective view of microwave field-detecting needleassembly including a needle assembly and a handle assembly according toan embodiment of the present disclosure;

FIG. 2 is an enlarged, cross-sectional view of the indicated area ofdetail of FIG. 1 showing a distal portion of the needle assemblyaccording to an embodiment of the present disclosure;

FIG. 3 is an enlarged view of the indicated area of detail of FIG. 1showing a schematic diagram of an electric circuit (shown in phantomlines in FIG. 1) disposed within the handle assembly according to anembodiment of the present disclosure;

FIG. 4 is perspective view of a microwave field-detecting systemincluding an embodiment of a microwave field-detecting needle assemblyand an embodiment of a control unit in accordance with the presentdisclosure;

FIG. 5 is perspective view with parts separated of the microwavefield-detecting needle assembly of FIG. 1 according to an embodiment ofthe present disclosure;

FIG. 6 is perspective view of an inner-conductor pin including a distalend configured with a retaining portion according to an embodiment ofthe present disclosure;

FIG. 7 is perspective view of a portion of a needle assembly including afirst outer-conductor structure coupled to the retaining portion anddisposed around a distal portion of the inner-conductor pin shown inFIG. 6 according to an embodiment of the present disclosure;

FIG. 8 is a perspective view of the portion of the needle assembly ofFIG. 7 shown with a tubular sleeve member disposed around a length ofthe inner-conductor pin proximal to the threaded portion according to anembodiment of the present disclosure;

FIG. 9 is a perspective view of the portion of the needle assembly ofFIG. 8 shown with a junction structure disposed around a portion of thetubular sleeve member and threadedly coupled to the proximal end of thefirst outer-conductor structure according to an embodiment of thepresent disclosure;

FIG. 10 is a perspective view of the portion of the needle assembly ofFIG. 9 shown with a second outer-conductor structure disposed around aproximal portion of the tubular sleeve member and threadedly coupled tothe distal end of the junction structure, according to an embodiment ofthe present disclosure;

FIG. 11 is a perspective view of the portion of the needle assembly ofFIG. 10 shown with a rectifier element disposed separately from andpositioned above a rectifier-receiving recess defined in the junctionstructure according to an embodiment of the present disclosure;

FIG. 12 is a perspective view of the portion of the needle assembly ofFIG. 11 shown with the rectifier element disposed in therectifier-receiving recess according to an embodiment of the presentdisclosure;

FIG. 13 is a perspective view of the portion of the needle assembly ofFIG. 12 shown with an outer jacket disposed around the firstouter-conductor structure, second outer-conductor structure and thejunction structure according to an embodiment of the present disclosure;

FIG. 14 is a cross-sectional view of the portion of the needle assemblyof FIG. 13 according to an embodiment of the present disclosure;

FIG. 15 is a schematically-illustrated representation of a standing wavecoupled to the needle assembly of FIG. 13 according to an embodiment ofthe present disclosure;

FIG. 16 is a perspective view of a first side of another embodiment of aneedle assembly in accordance with the present disclosure;

FIG. 17 is a perspective view of a second side of the needle assembly ofFIG. 16 according to an embodiment of the present disclosure;

FIG. 18 is a schematic perspective view of an electrosurgical systemaccording to an embodiment of the present disclosure;

FIG. 19 is a block diagram of an embodiment of the electrosurgical powergenerating source of FIG. 18 in accordance with the present disclosure;

FIG. 20 is a flowchart illustrating a method of method of manufacturinga needle assembly according to an embodiment of the present disclosure;

FIG. 21 is a flowchart illustrating a method of method of manufacturinga microwave field-detecting needle assembly according to an embodimentof the present disclosure; and

FIG. 22 is a flowchart illustrating a method of adjusting an ablationfield radiating into tissue.

DETAILED DESCRIPTION

Hereinafter, embodiments of microwave field-detecting needle assemblies,methods of manufacturing the same, methods of adjusting an ablationfield radiating into tissue using the same, and systems including thesame of the present disclosure are described with reference to theaccompanying drawings. Like reference numerals may refer to similar oridentical elements throughout the description of the figures. As shownin the drawings and as used in this description, and as is traditionalwhen referring to relative positioning on an object, the term “proximal”refers to that portion of the apparatus, or component thereof, closer tothe user and the term “distal” refers to that portion of the apparatus,or component thereof, farther from the user.

This description may use the phrases “in an embodiment,” “inembodiments,” “in some embodiments,” or “in other embodiments,” whichmay each refer to one or more of the same or different embodiments inaccordance with the present disclosure. For the purposes of thisdescription, a phrase in the form “A/B” means A or B. For the purposesof the description, a phrase in the form “A and/or B” means “(A), (B),or (A and B)”. For the purposes of this description, a phrase in theform “at least one of A, B, or C” means “(A), (B), (C), (A and B), (Aand C), (B and C), or (A, B and C)”.

Electromagnetic energy is generally classified by increasing energy ordecreasing wavelength into radio waves, microwaves, infrared, visiblelight, ultraviolet, X-rays and gamma-rays. As it is used in thisdescription, “microwave” generally refers to electromagnetic waves inthe frequency range of 300 megahertz (MHz) (3×10⁸ cycles/second) to 300gigahertz (GHz) (3×10¹¹ cycles/second). As it is used in thisdescription, “transmission line” generally refers to any transmissionmedium that can be used for the propagation of signals from one point toanother.

As it is used in this description, “ablation procedure” generally refersto any ablation procedure, such as, for example, microwave ablation,radiofrequency (RF) ablation, or microwave or RF ablation-assistedresection. As it is used in this description, “energy applicator”generally refers to any device that can be used to transfer energy froma power generating source, such as a microwave or RF electrosurgicalgenerator, to tissue. For the purposes herein, the term “energyapplicator” is interchangeable with the term “energy-delivery device”.

As it is used in this description, “rectifier” generally refers tocircuit components that allow more electric current to flow in onedirection than in the other. Rectifiers may be made of solid-statediodes, vacuum-tube diodes, mercury-arc valves, and other components.Processes that make use of rectifiers include rectification, which,simply defined, is the conversion of alternating current (AC) to directcurrent (DC). As it is used in this description, “diode” generallyrefers to electronic devices that allow electric current to flow in onlyone direction, while inhibiting current flow in the other. For thepurposes herein, the term “diode” is interchangeable with the term“rectifier”.

As it is used in this description, “printed circuit board” (or “PCB”)generally refers to any and all systems that provide, among otherthings, mechanical support to electrical components, electricalconnection to and between these electrical components, combinationsthereof, and the like.

As it is used in this description, “length” may refer to electricallength or physical length. In general, electrical length is anexpression of the length of a transmission medium in terms of thewavelength of a signal propagating within the medium. Electrical lengthis normally expressed in terms of wavelength, radians or degrees. Forexample, electrical length may be expressed as a multiple orsub-multiple of the wavelength of an electromagnetic wave or electricalsignal propagating within a transmission medium. The wavelength may beexpressed in radians or in artificial units of angular measure, such asdegrees. The electric length of a transmission medium may be expressedas its physical length multiplied by the ratio of (a) the propagationtime of an electrical or electromagnetic signal through the medium to(b) the propagation time of an electromagnetic wave in free space over adistance equal to the physical length of the medium. The electricallength is in general different from the physical length. By the additionof an appropriate reactive element (capacitive or inductive), theelectrical length may be made significantly shorter or longer than thephysical length.

Various embodiments of the present disclosure provide microwavefield-detecting needle assemblies adapted to enable physicians to detectmicrowave field intensity in proximity to an energy-delivery devices,e.g., to ensure patient and/or physician safety and/or to provide forimproved control over applied energy. Microwave field-detecting needleassembly embodiments may be implemented as passive devices. In someembodiments, microwave field-detecting needle assemblies may bemonitored by a stand-alone control unit. Microwave field-detectingneedle assembly embodiments may be integrated into a feedback controlloop within a microwave ablation control system.

Microwave field-detecting needle assembly embodiments may be suitablefor utilization in open surgical applications. Embodiments may be usedin minimally invasive procedures, e.g., endoscopic and laparoscopicsurgical procedures. Portions of the presently-disclosed microwavefield-detecting needle assemblies may be disposable, replaceable and/orreusable.

Various embodiments of the presently-disclosed microwave field-detectingneedle assembly are adapted to be coupled in communication with astand-alone control unit (e.g., 28 shown in FIG. 4).

An electrosurgical system (also referred to herein as a “microwaveablation control system”) including an energy-delivery device(s) and oneor more microwave field-detecting needle assemblies according to variousembodiments is designed and configured to operate at frequencies betweenabout 300 MHz and about 10 GHz. The presently-disclosed microwaveablation control systems are suitable for microwave or RF ablation andfor use to pre-coagulate tissue for microwave or RF ablation-assistedsurgical resection. In addition, although the following descriptiondescribes embodiments of a microwave field-detecting needle assemblycapable of detecting electromagnetic radiation at microwave frequencies,the teachings of the present disclosure may also apply toelectromagnetic radiation at RF frequencies or at other frequencies.

FIGS. 1 through 3 show an embodiment of a microwave field-detectingneedle assembly (shown generally as 100 in FIG. 1). Microwavefield-detecting needle assembly 100 generally includes a handle assembly170 and a needle assembly 110. FIG. 3 shows a schematic diagram of anelectric circuit 300 (shown in phantom lines in FIG. 1) disposed withina handle housing 174 of the handle assembly 170. Needle assembly 110 isshown with parts separated in FIG. 5.

As shown in FIGS. 1, 2 and 5, the needle assembly 110 generally includesa distal portion 130, a proximal portion 160, and a junction member 150disposed between the distal portion 130 and the proximal portion 160. Insome embodiments, the distal portion 130 and the proximal portion 160align at the junction member 150, which is generally made of adielectric material. In some embodiments, the junction member 150 may beconfigured to be mechanically coupleable (e.g., threadedly coupleable)to the distal portion 130 and/or the proximal portion 160. In someembodiments, the distal portion 130 includes a first outer-conductorstructure 30, the proximal portion 160 includes a second outer-conductorstructure 60, and the junction member 150 includes a junction structure50. The shape and size of the needle assembly 110 and the handleassembly 170 may be varied from the configuration depicted in FIG. 1.

As shown in FIGS. 2 and 5, needle assembly 110 includes aninner-conductor pin 20, a tubular sleeve member 40 disposed around atleast a portion of the inner-conductor pin 20, a first outer-conductorstructure 30, a second outer-conductor structure 60, a junctionstructure 50 disposed between the first outer-conductor structure 30 andthe second outer-conductor structure 60, and one or more rectifiers 58disposed in one or more recesses 56 defined in the junction structure50. Inner-conductor pin 20 has a suitable outer diameter “D₁” (FIG. 5).The distal end 22 of the inner-conductor pin 20 includes a retainingportion 23. In some embodiments, the retaining portion 23 may beexternally threaded. In one embodiment, the proximal end 21 of theinner-conductor pin 20 is coupled to the handle assembly 170.Inner-conductor pin 20 may be electrically coupled to an electriccircuit 300, which is described in more detail later in this disclosure,disposed within the handle assembly 170.

Various components of the needle assembly 110 may be formed of suitable,electrically-conductive materials, e.g., copper, gold, silver, or otherconductive metals or metal alloys having similar conductivity values.Electrically-conductive materials used to form the inner-conductor pin20, the first outer-conductor structure 30 and/or the secondouter-conductor structure 60 may be plated with other materials, e.g.,other conductive materials, such as gold or silver, to improve theirproperties, e.g., to improve conductivity, decrease energy loss, etc.

In some embodiments, the inner-conductor pin 20, the firstouter-conductor structure 30 and/or the second outer-conductor structure60 may be formed of a rigid, electrically-conductive material, such asstainless steel. In some embodiments, the inner-conductor pin 20 isformed from a first electrically-conductive material (e.g., stainlesssteel) and the first outer-conductor structure 30 and/or the secondouter-conductor structure 60 is formed from a secondelectrically-conductive material (e.g., copper). In some embodiments,the inner-conductor pin 20, the first outer-conductor structure 30and/or the second outer-conductor structure 60 may be formed of aflexible, electrically-conductive material, such as titanium.

Tubular sleeve member 40 includes a body 44 that defines alongitudinally-extending internal bore or chamber 45 configured toreceive at least a portion of the inner-conductor pin 20 therein. Body44 has a suitable outer diameter “D₂” as shown in FIG. 5. Tubular sleevemember 40 may be formed from any suitable dielectric material,including, but not limited to, ceramics, mica, polyethylene,polyethylene terephthalate, polyimide, polytetrafluoroethylene (PTFE)(e.g., TEFLON®, manufactured by E. I. du Pont de Nemours and Company ofWilmington, Del., United States), glass, metal oxides or other suitableinsulator, and may be formed in any suitable manner. In the embodimentshown in FIG. 2, tubular sleeve member 40 is disposed around a length ofthe inner-conductor pin 20 proximal to the retaining portion 23.

Junction member embodiments in accordance with the present disclosureinclude a junction structure having one or more recesses (e.g., onerecess 56 shown in FIGS. 2, 5 and 9-12, or a plurality of recesses 1656shown in FIG. 16) defined therein. As best shown in FIG. 11, the recess56 is configured to receive a rectifier 58 therein. Rectifier 58 mayinclude one or more diodes, e.g., Zener diode, Schottky diode, tunneldiode and the like, and/or other suitable component(s) capable ofconverting AC to DC.

Junction structure 50 may be formed of any suitable elastomeric orceramic dielectric material by any suitable process. In someembodiments, the junction structure 50 may be formed of a compositematerial having low electrical conductivity, e.g., glass-reinforcedpolymers. In some embodiments, the junction structure 50 is formed byover-molding and includes a thermoplastic elastomer, such as, forexample, polyether block amide (e.g., PEBAX®, manufactured by The ArkemaGroup of Colombes, France), polyetherimide (e.g., ULTEM® and/or EXTEM®,manufactured by SABIC Innovative Plastics of Saudi Arabia) and/orpolyimide-based polymer (e.g., VESPEL®, manufactured by E. I. du Pont deNemours and Company of Wilmington, Del., United States). Junctionstructure 50 may be formed using any suitable over-molding compound byany suitable process, and may include use of a ceramic substrate.

In an embodiment, as best shown in FIG. 3, electric circuit 300 isdisposed within the handle housing 174 of the handle assembly 170. Inone embodiment, electric circuit 300 may be formed as a printed circuitboard, with components thereof connected by traces on an epoxy resinsubstrate.

Handle housing 174 provides a ground reference “G” for the circuit 300.An indicator unit 4, or component thereof, is coupled to the handlehousing 174. Indicator unit 4 may include audio and/or visual indicatordevices to provide information/feedback to a user. In the embodimentshown in FIGS. 1 and 3, the indicator unit 4 is adapted to generate avisual signal and includes a light source, such as a light-emittingdiode 9. Indicator unit 4 may additionally, or alternatively, be adaptedto generate an audio signal and may include an audio circuit with aspeaker (not shown).

The proximal end 21 of the inner-conductor pin 20 (shown in crosssection in FIG. 3) is electrically coupled to a first terminal of afilter circuit 5. Filter circuit 5 includes a second terminalelectrically coupled to an amplifier circuit 7, and may include a groundterminal electrically coupled to the handle housing 174. Filter circuit5 may include an RF filter block. In one embodiment, the filter circuit5 may be an inductor-resistor-capacitor (LCR) low-pass filter that isadapted to convert a rectified sinusoidal waveform from the rectifierelements 58 into an electrical signal, which may be a DC voltage signalrepresentative of the detected microwave field intensity.

As shown in FIG. 3, circuit 300 includes a power source 3 that iselectrically coupled to the amplifier circuit 7. Power source 3 mayinclude a ground terminal electrically coupled to the handle housing174. Power source 3 may include any combination of battery cells, abattery pack, fuel cell and/or high-energy capacitor. A battery pack mayinclude one or more disposable batteries. In such case, the one or moredisposable batteries may be used as a primary power source for theamplifier circuit 7. In some embodiments, a transmission line 11(FIG. 1) is provided to connect the microwave field-detecting needleassembly to a line source voltage or external power source (showngenerally as 2 in FIG. 1), in which case a battery pack may be providedfor use as a backup power source.

FIG. 4 schematically illustrates an embodiment of a microwavefield-detecting system (shown generally as 10) that includes astand-alone control unit 28 operably coupled to a microwavefield-detecting needle assembly 400. Microwave field-detecting needleassembly 400 is similar to the microwave field-detecting needle assembly100 of FIG. 1, except that microwave field-detecting needle assembly 400includes a handle assembly 470 configured to operably couple the needleassembly 110 to a cable assembly 15. Cable assembly 15 may be anysuitable transmission line. Cable assembly 15 may include a proximal end14 suitable for connection to the control unit 28.

Handle assembly 470 includes an indicator unit 412 that is suitablyconfigured to provide information/feedback to a user. Indicator unit 412is similar to the indicator unit 4 shown in FIG. 3 and furtherdescription thereof is omitted in the interests of brevity. The shapeand size of the handle assembly 470 and the indicator unit 412 may bevaried from the configuration depicted in FIG. 4.

Control unit 28 may include a user interface 27 in operablecommunication with a processor unit 29. User interface 27 may includeaudio and/or visual indicator devices to provide information/feedback toa user. Processor unit 29 may be any type of computing device,computational circuit, or any type of processor or processing circuitcapable of executing a series of instructions that are stored in amemory (not shown) associated with the processor unit 29. Processor unit29 may be adapted to run an operating system platform and applicationprograms. Microwave field-detecting needle assembly 400 and the controlunit 28 may utilize wired communication and/or wireless communication.In the embodiment illustrated in FIG. 4, the microwave field-detectingneedle assembly 400 is electrically connected via the cable assembly 15to a connector 16, which further operably connects the microwavefield-detecting needle assembly 400 to a terminal 19 of the control unit28.

FIG. 5 shows the needle assembly 110 with parts separated in accordancewith the present disclosure. As described above with reference to FIG.2, the needle assembly 110 includes an inner-conductor pin 20, firstouter-conductor structure 30, second outer-conductor structure 60,tubular sleeve member 40, junction structure 50, and one or morerectifiers 58.

As shown in FIG. 5, the first outer-conductor structure 30 defines afirst chamber portion 36 and a second chamber portion 35. First chamberportion 36 is disposed at the distal end 32 of the first outer-conductorstructure 30. Second chamber portion 35 is disposed in communicationwith the first chamber portion 36 and includes an opening disposed atthe proximal end 31 of the first outer-conductor structure 30. In someembodiments, the first chamber portion 36 is configured to matinglyengage, e.g., threadedly engage, with the retaining portion 23 ofinner-conductor pin 20, and the second chamber portion 35 is configuredto receive at least a portion of the tubular sleeve member 40 therein.

First outer-conductor structure 30 may be provided with an end cap 37.End cap 37 generally includes a tapered portion 33, which may terminatein a sharp tip 34 to allow for insertion into tissue with minimalresistance. Tapered portion 33 may include other shapes, such as, forexample, a tip 34 that is rounded, flat, square, hexagonal, orcylindroconical. End cap 37 may be formed of a material having a highdielectric constant, and may be a trocar, e.g., a zirconia ceramic.First outer-conductor structure 30 and end cap 37 may be formedseparately from each other, and coupled together, e.g., with the aid ofadhesive or solder. First outer-conductor structure 30 and end cap 37may form a single, unitary structure. The shape and size of the firstouter-conductor structure 30 and the end cap 37 may be varied from theconfiguration depicted in FIG. 5.

Second outer-conductor structure 60 defines a longitudinally-extendinginternal bore or chamber 65 that extends from the proximal end 61 to thedistal end 62 of the second outer-conductor structure 60. Chamber 65 isconfigured to receive at least a portion of the tubular sleeve member 40therein.

Junction structure 50 defines a longitudinally-extending internal boreor chamber 55 therein and generally includes a distal end 52 adapted forconnection to the first outer-conductor structure 30 and a proximal end51 adapted for connection to the second outer-conductor structure 60. Insome embodiments, the junction structure 50 includes a distal end 52provided with a series of external threads configured to matingly engagewith a series of internal threads disposed at the proximal end 31 of thefirst outer-conductor structure 30, and a proximal end 51 provided witha series of external threads configured to matingly engage with a seriesof internal threads disposed at the distal end 62 of the secondouter-conductor structure 60. The shape and size of the junctionstructure 50 may be varied from the configuration depicted in FIG. 5.

FIGS. 6 through 13 show a sequentially-illustrated, assembly ofcomponents forming the needle assembly 110 in accordance with thepresent disclosure. FIG. 6 shows the inner-conductor pin 20. Asdescribed above, inner-conductor pin 20 may be formed of any suitableelectrically-conductive material (e.g., metal such as stainless steel,aluminum, titanium, copper, etc.) of any suitable length. The shape andsize of the inner-conductor pin 20 may be varied from the configurationdepicted in FIG. 6.

As cooperatively shown in FIGS. 6 and 7, inner-conductor pin 20 includesa distal end 22 including a retaining portion 23 that is configured tobe connectable, e.g., electrically and mechanically, to the firstouter-conductor structure 30. In some embodiments, the retaining portion23 is provided with a series of external threads configured to matinglyengage with a series of internal threads disposed within the firstchamber portion 36 of the first outer-conductor structure 30.Alternatively, mechanical fasteners, grooves, flanges, adhesives, andwelding processes, e.g., laser welding, or other suitable joining methodmay be used to attach (or clip, connect, couple, fasten, secure, etc.)the inner-conductor pin 20 to the first outer-conductor structure 30. Asshown in FIG. 7, a longitudinal axis “A′-A” is defined by theinner-conductor pin 20.

As cooperatively shown in FIGS. 8 through 10, tubular sleeve member 40is configured to be receivable within second chamber portion 35 of thefirst outer-conductor structure 30, chamber 55 of the junction structure50 and chamber 60 of the second outer-conductor structure 60. FIG. 8shows the tubular sleeve member 40 joined together with theinner-conductor pin 20 and the first outer-conductor structure 30 suchthat the tubular sleeve member 40 is coaxially-disposed about the lengthof the inner conductor 20 proximal to the retaining portion 23 anddisposed at least in part within the second chamber portion 35 of thefirst outer-conductor structure 30. In an embodiment, the tubular sleevemember 40 is positioned around the inner-conductor pin 20 after theretaining portion 23 is coupled to the end cap 37, e.g., as shown inFIG. 8. Tubular sleeve member 40 may, alternatively, be positioned,formed, adhered or otherwise disposed around at least a portion of theinner-conductor pin 20 prior to the introduction of the inner-conductorpin 20 into the second chamber portion 35 of the first outer-conductorstructure 30.

FIG. 9 shows the portion of the needle assembly of FIG. 8 shown withjunction structure 50 disposed around a portion of the tubular sleevemember 40 and coupled to the first outer-conductor structure 30.Junction structure 50 may be coupled to the first outer-conductorstructure 30 by any suitable manner of connection. In the embodimentshown in FIG. 9, junction structure 50 includes a distal end 52 providedwith a series of external threads configured to matingly engage with aseries of internal threads disposed at the proximal end 31 of the firstouter-conductor structure 30. The junction structure 50 and the firstouter-conductor structure 30 (as well as other components describedherein) may be assembled together with the aid of alignment pins,snap-like interfaces, tongue and groove interfaces, locking tabs,adhesive ports, etc., utilized either alone or in combination forassembly purposes.

FIG. 10 shows the portion of the needle assembly of FIG. 9 shown withsecond outer-conductor structure 60 disposed around a portion of thetubular sleeve member 40 and coupled to the proximal end 51 of thejunction structure 50. In the embodiment shown in FIG. 10, secondouter-conductor structure 60 includes a distal end 62 provided with aseries of internal threads configured to matingly engage with a seriesof external threads disposed at the proximal end 51 of the junctionstructure 50.

FIG. 11 shows the portion of the needle assembly of FIG. 10 shown withrectifier element 58 disposed above rectifier-receiving recess 56 in thejunction structure 50. Rectifier element 58 includes a first lead wireor pin 59 a (also referred to herein as a “terminal”) and a second leadwire or pin 59 b. Rectifier-receiving recess 56 may be configured toreceive the rectifier element 58 such that the first pin 59 a and thesecond pin 59 b are substantially aligned with the longitudinal axis“A′-A” defined by the inner-conductor pin 20.

FIG. 12 shows the portion of the needle assembly of FIG. 11 shown withthe rectifier element 58 disposed in the rectifier-receiving recess 56.First pin 59 a is electrically coupled to the first outer-conductorstructure 30 by any suitable manner of electrical connection, e.g.,soldering, welding, or laser welding. Second pin 59 b is electricallycoupled to the second outer-conductor 60 by any suitable manner ofelectrical connection.

FIG. 13 shows the portion of the needle assembly of FIG. 12 shown withan outer jacket 90 disposed around the first outer-conductor structure30, the second outer-conductor structure 60, and the junction structure50. Outer jacket 90 may be formed of any suitable material, such as, forexample, polymeric or ceramic materials. The outer jacket 90 may beapplied by any suitable method, such as, for example, heat-shrinkage,extrusion, molding, coating, spraying, dipping, powder coating, bakingand/or film deposition, or other suitable process.

In an embodiment, as best shown in FIG. 14, which shows the crosssection of the needle assembly portion of FIG. 13, outer jacket 90covers the rectifier element 58. In alternative embodiments, the outerjacket 90 may include an opening (not shown) configured to expose therectifier element 58 and/or the junction structure 50, or portionthereof.

The position of the junction structure 50 and rectifier element 58,e.g., in relation to the tip 34, is one factor in determining theoperational frequency of the microwave field-detecting needle assembly100 in a given material, e.g., tissue. To obtain a microwavefield-detecting needle assembly having a desired frequency, the junctionstructure 50 may be positioned at a location of high voltage along theexpected standing wave that couples onto the probe, such asillustratively shown in FIG. 15. During a procedure, e.g., an ablationprocedure, fields 1501, 1502 couple onto the microwave field-detectingneedle assembly 100 from the energy supplied by an energy-deliverydevice (e.g., 12 shown in FIG. 18), e.g., a microwave ablation probe.

FIGS. 16 and 17 show a needle assembly (shown generally as 1610)according to an embodiment of the present disclosure that is adapted toenable multi-frequency operation and/or multiple wavelength operation.Needle assembly 1610 is similar to the needle assembly 110 shown inFIGS. 1, 2 and 5, except for the configuration of the junction structure1650, the first outer-conductor structure 1630 and the secondouter-conductor structure 1660, and the plurality of rectifiers 1658disposed in the plurality of recesses 1656.

Needle assembly 1610 includes a junction structure 1650 configured toseparate a first outer-conductor structure 1630 and a secondouter-conductor structure 1660 in a diagonal fashion. Firstouter-conductor structure 1630 and the second outer-conductor structure1660 may be formed of any suitable electrically-conductive material,e.g., metal such as stainless steel, aluminum, titanium, copper, or thelike. In some embodiments, the first outer-conductor structure 1630 isconstructed from stainless steel, and may be coated in a high electricalconductivity, corrosion-resistant metal, e.g., silver, or the like.

As best shown in FIG. 16, the junction structure 1650 includes aplurality of recesses 1656 defined therein, wherein each recess 1656 isdefined in a different outer-peripheral portion of the junctionstructure 1650 and configured to receive a rectifier 1658 therein.Rectifier 1658 is similar to the rectifier 58 shown in FIG. 2 andfurther description thereof is omitted in the interests of brevity. Eachrectifier 1658 may be configured to operate efficiently at separatefrequencies allowing for probe use at multiple frequencies.

FIG. 18 shows an electrosurgical system 1800 according to an embodimentof the present disclosure that includes an energy applicator or probe 12operably coupled to an electrosurgical power generating source 26. Insome embodiments, the probe 12 may be coupled in fluid communicationwith a coolant supply system (not shown).

Electrosurgical system 1800 (also referred to herein as a “microwaveablation control system”) generally includes one or more microwavefield-detecting needle assemblies 100 and a control unit 24 in operablecommunication with the one or more microwave field-detecting needleassemblies 100. Control unit 24 and the one or more microwavefield-detecting needle assemblies 100 may utilize wired communicationand/or wireless communication. Control unit 24 is similar to the controlunit 28 shown in FIG. 4 and further description thereof is omitted inthe interests of brevity. Electrosurgical system 1800 according tovarious embodiments may include a feedback loop 18 suitable for use incontrolling an energy applicator or probe 12 based on one or moreelectrical signals transmitted by one or more microwave field-detectingneedle assemblies 100. Feedback loop 18 may utilize a cable connectionand/or a wireless connection, e.g., a radiofrequency or infrared link.

In some embodiments, the microwave ablation control system 1800 mayadjust the ablation field radiating about at least a portion of theenergy applicator 12 into tissue by adjusting one or more operatingparameters associated with the electrosurgical power generating source26 based on one or more electrical signals transmitted by one or moremicrowave field-detecting needle assemblies 100. In the embodimentillustrated in FIG. 18, the plurality of microwave field-detectingneedle assemblies 100 in operable communication with the control unit 24are operable coupled via the feedback loop 18 to the electrosurgicalpower generating source 26. Examples of operating parameters associatedwith the electrosurgical power generating source 26 include temperature,impedance, power, current, voltage, mode of operation, and duration ofapplication of electromagnetic energy.

It is to be understood that, although one energy applicator 12 and threemicrowave field-detecting needle assemblies 100 are shown in FIG. 18,electrosurgical system embodiments may utilize single or multiple energyapplicators (or applicator arrays) and one or more microwavefield-detecting needle assemblies. The single or multiple energyapplicators and the one or more microwave field-detecting needleassemblies may be arranged in any suitable configuration.

Electrosurgical power generating source 26 may be any generator suitablefor use with electrosurgical devices, and may be configured to providevarious frequencies of electromagnetic energy. In some embodiments, theelectrosurgical power generating source 26 is configured to providemicrowave energy at an operational frequency from about 300 MHz to about10 GHz. In other embodiments, the electrosurgical power generatingsource 26 is configured to provide electrosurgical energy at anoperational frequency from about 400 KHz to about 500 KHz.

In some embodiments, the electrosurgical power generating source 26 isconfigured or set to a predetermined setting. For example,electrosurgical power generating source 26 may be set to a predeterminedtemperature, such as a temperature that may be used for the treatment ofpain (e.g., about 42° C. or about 80° C.), a predetermined waveform, apredetermined duty cycle, a predetermined time period or duration ofactivation, etc.

Electrosurgical power generating source 26 may include a user interface25 (FIG. 19) in operable communication with a processor unit 82 (FIG.19). Processor unit 82, which is described in more detail with respectto FIG. 19, may be any type of computing device, computational circuit,or any type of processor or processing circuit capable of executing aseries of instructions that are stored in a memory. In an embodiment, aphysician may input via the user interface 25 a selected power output,and the microwave ablation control system 1800 controls the probe 12 toautomatically adjust the ablation volume by changing the operatingfrequency of the probe 12, e.g., based on at least one electrical signaltransmitted by the one or more microwave field-detecting needleassemblies 100.

In an embodiment, a physician may input via the user interface 25 aselected power output, and the microwave ablation control system 1800controls the ablation field radiating about at least a portion of theenergy applicator 12 into tissue based on one or more electrical signalstransmitted by one or more microwave field-detecting needle assemblies100, e.g., by rotation of a energy applicator with a directionalradiation pattern to avoid ablating sensitive structures, such as largevessels, healthy organs or vital membrane barriers and/or by controllingthe electrosurgical power generating source 26 operatively associatedwith an energy applicator 12.

During microwave ablation using the microwave ablation control system1800, one or more microwave field-detecting needle assemblies 100 may beinserted into tissue “T” and/or placed adjacent a sensitive structure“S”, and/or one or more microwave field-detecting needle assemblies 100may be inserted into the abdominal wall “W” and/or into the abdominalcavity “C”. Probe 12 is inserted into tissue “T” and/or placed adjacentto a lesion “L”. Ultrasound or computed tomography (CT) guidance may beused to accurately guide the probe 12 into the area of tissue to betreated. Probe 12 and one or more microwave field-detecting needleassemblies 100 may be placed percutaneously or surgically, e.g., usingconventional surgical techniques by surgical staff. After the one ormore microwave field-detecting needle assemblies 100 and the probe 12are positioned, microwave energy is supplied to the probe 12.

A clinician may pre-determine the length of time that microwave energyis to be applied. Application duration may depend on many factors suchas tumor size and location and whether the tumor was a secondary orprimary cancer. The duration of microwave energy application using theprobe 12 may depend on the progress of the heat distribution within thetissue area that is to be destroyed and/or the surrounding tissue.Treatment of certain tumors may involve probe repositioning during theablation procedure, such as where the tumor is larger than the probe orhas a shape that does not correspond with available probe geometry orradiation pattern.

FIG. 19 is a block diagram showing one embodiment of the electrosurgicalpower generating source 26 of FIG. 18. In an embodiment, the generatormodule 86 is configured to provide energy of about 915 MHz. Generatormodule 86 may additionally, or alternatively, be configured to provideenergy of about 2450 MHz (2.45 GHz). The present disclosure contemplatesembodiments wherein the generator module 286 is configured to generate afrequency other than about 915 MHz or about 2450 MHz, and embodimentswherein the generator module 86 is configured to generate variablefrequency energy. Electrosurgical power generating source 26 includes aprocessor 82 that is operably coupled to the user interface 25.Processor 82 may include any type of computing device, computationalcircuit, or any type of processor or processing circuit capable ofexecuting a series of instructions that are stored in a memory, e.g.,storage device 88 or external device 91.

In some embodiments, storage device 88 is operably coupled to theprocessor 82, and may include random-access memory (RAM), read-onlymemory (ROM), and/or non-volatile memory (NV-RAM, Flash, and disc-basedstorage). Storage device 88 may include a set of program instructionsexecutable on the processor 82 for executing a method for displaying andcontrolling ablation patterns in accordance with the present disclosure.Electrosurgical power generating source 26 may include a data interface90 that is configured to provide a communications link to an externaldevice 91. In some embodiments, the data interface 90 may be any of aUSB interface, a memory card slot (e.g., SD slot), and/or a networkinterface (e.g., 100BaseT Ethernet interface or an 802.11 “Wi-Fi”interface.) External device 91 may be any of a USB device (e.g., amemory stick), a memory card (e.g., an SD card), and/or anetwork-connected device (e.g., computer or server).

Electrosurgical power generating source 26 may also include a database84 that is configured to store and retrieve energy applicator data,e.g., parameters associated with one or energy applicators (e.g., 12shown in FIGS. 18 and 19). Parameters stored in the database 84 inconnection with an energy applicator, or energy applicator array, mayinclude, but are not limited to, energy applicator (or applicator array)identifier, energy applicator (or applicator array) dimensions, afrequency, an ablation length, an ablation diameter, a temporalcoefficient, a shape metric, and/or a frequency metric. In anembodiment, ablation pattern topology may be included in the database84, e.g., a wireframe model of an applicator array and/or an ablationpattern associated therewith and/or an arrangement of microwavefield-detecting needle assemblies for use in connection with one or moreenergy applicators.

Database 84 may also be maintained at least in part by data provided bythe external device 91 via the data interface 90. For example withoutlimitation, data associated with energy applicator 12 may be uploadedfrom an external device 91 to the database 84 via the data interface 90.Energy applicator data may additionally, or alternatively, bemanipulated, e.g., added, modified, or deleted, in accordance with dataand/or instructions stored on the external device 91. In an embodiment,the set of energy applicator data represented in the database 84 isautomatically synchronized with corresponding data contained in theexternal device 91 in response to the external device 91 being coupled(e.g., physical coupling and/or logical coupling) to the data interface90.

Processor 82 according to various embodiments is programmed to enable auser, via the user interface 25 and/or a display device (not shown), toview at least one ablation pattern and/or other data corresponding to anenergy applicator or an applicator array. For example, a physician maydetermine that a substantially spherical ablation pattern is necessary.The physician may activate a “select ablation shape” mode of operationfor electrosurgical power generating source 26, preview an energyapplicator array by reviewing graphically and textually presented data,optionally, or alternatively, manipulate a graphic image by, forexample, rotating the image, and select an energy applicator or anapplicator array, based upon displayed parameters. The selected energyapplicator(s) may then be electrically coupled to the electrosurgicalpower generating source 26 for use therewith.

Electrosurgical power generating source 26 may include an actuator 87.Actuator 87 may be any suitable actuator, e.g., a footswitch, ahandswitch, an orally-activated switch (e.g., a bite-activated switchand/or a breath-actuated switch), and the like. Actuator 87 may beoperably coupled to the processor 82 by a cable connection (e.g., 83shown in FIG. 18) or a wireless connection, e.g., a radiofrequency orinfrared link.

In an embodiment, a physician may input via the user interface 25 anapplicator array parameter to cause the electrosurgical power generatingsource 26 to present one or more electromagnetic energy delivery devicescorresponding thereto and/or one or more microwave field-detectingneedle assemblies for use therewith. For example, a physician mayrequire a 3.0 cm×3.0 cm×3.0 cm ablation pattern, and provide an inputcorresponding thereto. In response, the electrosurgical power generatingsource 26 may preview a corresponding subset of availableelectromagnetic energy delivery devices that match or correlate to theinputted parameter.

In an embodiment, a physician may input via the user interface 25 aselected power output, and the electrosurgical system 1800 controls theenergy applicator 12 to adjust the ablation field radiating about atleast a portion of the energy applicator 12 into tissue based on atleast one electrical signal transmitted by the one or more microwavefield-detecting needle assemblies.

Hereinafter, a method of manufacturing a needle assembly in accordancewith the present disclosure is described with reference to FIG. 20, amethod of manufacturing a microwave field-detecting needle assembly inaccordance with the present disclosure is described with reference toFIG. 21, and a method of adjusting an ablation field radiating intotissue is described with reference to FIG. 22. It is to be understoodthat the steps of the methods provided herein may be performed incombination and in a different order than presented herein withoutdeparting from the scope of the disclosure.

FIG. 20 is a flowchart illustrating a method of manufacturing a needleassembly according to an embodiment of the present disclosure. In step2010, an inner-conductor pin 20 is provided. A retaining portion 23 isdisposed at a distal end 22 of the inner-conductor pin 20.

In step 2020, a first outer-conductor structure 30 is joined to theretaining portion 23.

In step 2030, a tubular sleeve member 40 is positioned overlying alength of the inner-conductor pin 20 proximal to the retaining portion23. The tubular sleeve member 40 includes a longitudinally-extendinginternal chamber 45 configured to receive at least a portion of theinner-conductor pin 20 therein.

In step 2040, a junction structure 50 is joined to the proximal end 31of the first outer-conductor structure 30, whereby the junctionstructure 50 is disposed around a portion of the tubular sleeve member40. The junction structure 50 includes a recess 56 defined therein. Thedistal end 52 of the junction member 50 may be provided with a series ofexternal threads configured to matingly engage with a series of internalthreads disposed at the proximal end 31 of the first outer-conductorstructure 30.

In step 2050, a second outer-conductor structure 60 is joined to theproximal end 51 of the junction structure 50. The proximal end 51 of thejunction member 50 may be provided with a series of external threadsconfigured to matingly engage with a series of internal threads disposedat the distal end 62 of the second outer-conductor structure 60.

In step 2060, a rectifier element 58 is position into the recess 56. Insome embodiments, the rectifier element 58 includes a first terminal 59a and a second terminal 59 b. In such cases, the first terminal 59 a maybe electrically coupled to the first outer-conductor structure 30 andthe second terminal 59 b may be electrically coupled to the secondouter-conductor structure 60, e.g., by solder or other suitableelectrical connection.

FIG. 21 is a flowchart illustrating a method of manufacturing amicrowave field-detecting needle assembly according to an embodiment ofthe present disclosure. In step 2110, a handle assembly 170 is provided.An electric circuit 300 is disposed within the handle assembly 170.

In step 2120, a needle assembly 110 is provided. The needle assembly 110includes a first outer-conductor structure 30 coupled to aninner-conductor pin 20, a junction structure 50 disposed between thefirst outer-conductor structure 30 and a second outer-conductorstructure 60, and a rectifier element 58 disposed in a recess 56 definedin the junction structure 50. A first terminal 59 a of the rectifierelement 58 is electrically coupled to the first outer-conductorstructure 30, and a second terminal 59 b is electrically coupled to thesecond outer-conductor structure 60.

In step 2130, the inner-conductor pin 20 and the second outer-conductorstructure 60 are electrically coupled to an electric circuit 300disposed within the handle assembly 170.

FIG. 22 is a flowchart illustrating a method of adjusting an ablationfield radiating into tissue according to an embodiment of the presentdisclosure. In step 2210, an energy applicator 12 is provided. In step2220, one or more microwave field-detecting needle assemblies 100 areprovided. Each microwave field-detecting needle assembly 100 includesone or more rectifier elements 58 capable of detecting microwave fieldintensity via rectification.

In step 2230, the energy applicator 12 and the one or more microwavefield-detecting needle assemblies 100 are positioned in tissue. Theenergy applicator 12 may be inserted directly into tissue, insertedthrough a lumen, e.g., a vein, needle, endoscope or catheter, placedinto the body during surgery by a clinician, or positioned in the bodyby other suitable methods known in the art. The energy applicator 12 maybe configured to operate with a directional radiation pattern. The oneor more microwave field-detecting needle assemblies 100 may bepositioned in material, e.g., tissue, by any suitable method andarranged in any configuration (e.g., configuration shown in FIG. 18).

In step 2240, energy is transmitted from an energy source 26 through theenergy applicator 12 to generate an ablation field radiating about atleast a portion of the energy applicator 12 into tissue. The energysource 26 may be any suitable electrosurgical generator for generatingan output signal. In some embodiments, the energy source 26 is amicrowave energy source, and may be configured to provide microwaveenergy at an operational frequency from about 300 MHz to about 10 GHz.

In step 2250, the ablation field radiating about at least the portion ofthe energy applicator 12 into tissue is adjusted based on at least oneelectrical signal transmitted by the one or more microwavefield-detecting needle assemblies 100. In some embodiments, adjustingthe ablation field radiating about at least the portion of the energyapplicator 12 into tissue, in step 2250, may include adjusting at leastone operating parameter associated with the energy source 26 based onthe at least one electrical signal transmitted by the one or moremicrowave field-detecting needle assemblies 100. Examples of operatingparameters associated with the energy source 26 include temperature,impedance, power, current, voltage, mode of operation, and duration ofapplication of electromagnetic energy.

According to various embodiments of the present disclosure, theabove-described microwave field-detecting needle assembly enablesphysicians to detect field intensity in proximity to an energy-deliverydevice. The presently-disclosed microwave field-detecting needleassembly embodiments may allow the physician to determine if a microwavefield is strong enough for the intended purpose or to achieve a desiredsurgical outcome.

The presently-disclosed microwave field-detecting needle assemblyembodiments may be suitable for utilization in minimally invasiveprocedures, e.g., endoscopic and laparoscopic surgical procedures. Theabove-described microwave field-detecting needle assembly embodimentsmay be suitable for utilization in open surgical applications.

Various embodiments of the presently-disclosed microwave field-detectingneedle assembly embodiments may allow the physician to determine when amicrowave ablation probe is inserted to a proper depth within tissue,e.g., to reach the location of the ablation site and/or to avoidunintended field exposure. Various embodiments of thepresently-disclosed microwave field-detecting needle assembly areadapted to be coupled in communication with a stand-alone control unit.

Electrosurgical systems including one or more microwave field-detectingneedle assemblies according to embodiments of the present disclosure mayprotect sensitive structures, ensure expected field pattern and/orprotect the abdominal wall from stray microwave fields.

The above-described microwave field-detecting needle assemblies may beused to detect microwave field intensity emitted by an energyapplicator, and an electrical signal transmitted from thepresently-disclosed microwave field-detecting needle assemblies may beused to control the positioning of an electrosurgical device (e.g.,rotation of a energy applicator with a directional radiation pattern toavoid ablating sensitive structures, such as large vessels, healthyorgans or vital membrane barriers), and/or control an electrosurgicalpower generating source operatively associated with an energyapplicator.

Although embodiments have been described in detail with reference to theaccompanying drawings for the purpose of illustration and description,it is to be understood that the inventive processes and apparatus arenot to be construed as limited thereby. It will be apparent to those ofordinary skill in the art that various modifications to the foregoingembodiments may be made without departing from the scope of thedisclosure.

1. A method of adjusting an ablation field radiating into tissue,comprising the steps of: providing an energy applicator; providing atleast one microwave field-detecting needle assembly, the at least onemicrowave field-detecting needle assembly including at least onerectifier element capable of detecting microwave field intensity viarectification; positioning the energy applicator and the at least onemicrowave field-detecting needle assembly in tissue; transmitting energyfrom an energy source through the energy applicator to generate anablation field radiating about at least a portion of the energyapplicator into tissue; and adjusting the ablation field radiating aboutthe at least a portion of the energy applicator into tissue based on atleast one electrical signal transmitted by the at least one microwavefield-detecting needle assembly.
 2. The method of adjusting an ablationfield radiating into tissue of claim 1, wherein the energy source is anelectrosurgical power generating source.
 3. The method of adjusting anablation field radiating into tissue of claim 2, wherein the step ofadjusting the ablation field radiating about the at least a portion ofthe energy applicator into tissue includes the step of: adjusting atleast one operating parameter associated with the electrosurgical powergenerating source based on the at least one electrical signaltransmitted by the at least one microwave field-detecting needleassembly.
 4. The method of adjusting an ablation field radiating intotissue of claim 3, wherein the at least one operating parameterassociated with the electrosurgical power generating source is selectedfrom the group consisting of temperature, impedance, power, current,voltage, mode of operation, and duration of application ofelectromagnetic energy.
 5. A method of adjusting an ablation fieldradiating into tissue, comprising the steps of: providing an energyapplicator operably coupled to an energy source; providing at least onemicrowave field-detecting needle assembly, the at least one microwavefield-detecting needle assembly including at least one rectifier elementcapable of detecting microwave field intensity via rectification;positioning the energy applicator and the at least one microwavefield-detecting needle assembly in tissue; transmitting energy from anenergy source through the energy applicator to generate an ablationfield radiating about at least a portion of the energy applicator intotissue; and adjusting the ablation field radiating about the at least aportion of the energy applicator into tissue by adjusting at least oneoperating parameter associated with the energy source based on at leastone electrical signal transmitted by the at least one microwavefield-detecting needle assembly.
 6. The method of adjusting an ablationfield radiating into tissue of claim 5, wherein the at least oneoperating parameter associated with the energy source is selected fromthe group consisting of temperature, impedance, power, current, voltage,mode of operation, and duration of application of electromagneticenergy.
 7. A microwave ablation control system, comprising: a microwavefield-detecting needle assembly including at least one rectifier elementcapable of detecting microwave field intensity via rectification; acontrol unit in operable communication with the microwavefield-detecting needle assembly; an electrosurgical power generatingsource in operable communication with the control unit; and anenergy-delivery device operably coupled to the electrosurgical powergenerating source.
 8. The microwave ablation control system of claim 7,wherein the rectifier element is capable of converting alternatingcurrent (AC) to direct current (DC).
 9. The microwave ablation controlsystem of claim 8, wherein the rectifier element is a diode.
 10. Themicrowave ablation control system of claim 7, wherein the microwavefield-detecting needle assembly includes a needle assembly, the needleassembly including: a distal portion; a proximal portion; and a junctionmember disposed between the distal portion and the proximal portion, thejunction member including at least one recess defined therein, whereinthe at least one recess is configured to receive the at least onerectifier element therein.
 11. The microwave ablation control system ofclaim 10, further comprising a handle assembly operably coupled to aproximal end of the needle assembly.
 12. The microwave ablation controlsystem of claim 11, further comprising an electric circuit disposedwithin the handle assembly.
 13. The microwave ablation control system ofclaim 12, wherein the electric circuit includes a power source disposedwithin the handle assembly.
 14. The microwave ablation control system ofclaim 12, wherein the electric circuit includes an indicator unitadapted to generate at least one of a visual signal and an audio signal.15. The microwave ablation control system of claim 10, wherein themicrowave field-detecting needle assembly further includes a cableassembly having a proximal end suitable for connection to the controlunit, the cable assembly electrically coupled to the needle assembly viathe handle assembly.
 16. The microwave ablation control system of claim10, wherein the distal portion includes a first outer-conductorstructure.
 17. The microwave ablation control system of claim 16,wherein the first outer-conductor structure defines a first chamberportion disposed at a distal end of the first outer-conductor structure.18. The microwave ablation control system of claim 7, wherein theelectrosurgical power generating source includes a processor unit. 19.The microwave ablation control system of claim 18, wherein the processorunit is configured to adjust at least one operating parameter associatedwith the electrosurgical power generating source based on at least oneelectrical signal transmitted by the microwave field-detecting needleassembly.
 20. The microwave ablation control system of claim 19, whereinthe at least one operating parameter associated with the electrosurgicalpower generating source is selected from the group consisting oftemperature, impedance, power, current, voltage, mode of operation, andduration of application of electromagnetic energy.